Go to the general Navy recruiting site, select options as appropriate, be sure to select "officer." The officer warfare communities are available out of USNA, and Marine officer, ground and air. This is just to dip your toe in the (salt) water.
https://www.navy.com/joining/ways-to-join/career-comparison.html
Every Navy warfare community has a career description page.
Read EVERYTHING, every link, every drop down, at USNA Admissions site. Heaps of info about process, what to expect, etc.
Here on SAF, be sure to scan the Acronym Sticky at the top of the Community Information Forum. In fact, suggest reading all Stickies, at the top of various forums. And, since there is a yearly rhythm to questions, browse the USNA forum. Each year about this time, rising HS juniors get interested, and rising seniors get serious.
Search SAF USNA Forum on "Service selection" to see posts about how the class goes into different communities.
Just to answer a top-level question:
Surface Warfare: grads go direct to sea duty to first ship. Ships have a cycle of getting ready for deployment, deploying, returning, local operations, getting ready. Deployments can and do vary. Much depends on mission and type of ship. Six months is always a good rough estimate.
Aviation, submarine, EOD, SEAL - all have multi-year training pipelines. Then it's off to first operational duty assignment.
There are other cats and dogs, as well as the caveat that a small percentage of the class is allowed to go right to a Master's program, delaying reporting to their warfare path.
If you have the opportunity to visit USNA and attend the Admission briefing, that is helpful. Your DS will have the fun of researching all this and filling you in.
